Spagk-plirg



L. R. BENN. SPARK PLUG. APPLICATION man :uwn. 1917.

O "In n L66. 7- Bear;

glwuentoz Patented June 17, 1919.

inarrsn sra rss harass? LEE It. IBENN, OF TAMA, IOWA.

SPARK-PLUG.

To all whom it may concern:

Be it known that I, LEE R. BENN, a citizen of the United States,residing at T ama,

in the county of Tania and State of Iowa,

, electrode and short circuiting the device which will prevent itsproper operation. This type of spark plug will tend to keep the adjacentpoints of the spark gap clean, so as to insure a positive spark duringits operation.

The invention has for its primary object to provide an improvedelectrodeof novel construction, means being also provided to prevent theporcelain core from cracking when the plug becomes hot, and likewisewhich prevents leakage when the plug is cold.

A further object of the invention is to provide a device of thischaracter which is easily and simply constructed, inexpensive tomanufacture, and one which will be very eiiicient in operation.

With the above and other objects in view,

' as will'appear as the description proceeds,

the invention comprises the various novel features of construction andarrangement of parts which will be more fully described herein and setforth with particularity in the claim appended hereto.

"Reference is had to the accompanying drawings forming a part oi thisapplication, in which like reference characters indicate thecorresponding parts throughout the several views, in which Figure 1 1s aside elevation of my improved spark plug, partly in section,

Fig. ,2 is a bottom plan view thereof, and

'Fig. 3 is an enlarged detailed sectional viewof the lower end of themain electrode.

"Referring to the drawings in detail, 10

\ designates the porcelain core that is adapted to be positioned in theusual type of casing 11 provided with a wrench engaging surface in theusual manner and having its said lower end externally threaded as shownat 12 so as to permit connection with an engine cylinder.

he casing 11 is provided with I Specification of Letters Patent. Pate tJ u 9 V3 191%} Application filed July 11,

1918. Serial No. 244,419.

ranged between the casing and the core as.

is common to spark plugs of this character, said sleeve being insertedinto position to form the upper shoulder in the casing, as specified.These gaskets will prevent the core from breaking, when the plug is hot.as Well as to prevent leakage when the plug is cold.

The porcelain plug 10 has positioned centrally therethrough a mainelectrode 17 which project from the upper end oi the plug as a binding18 thereon for connecting a lead wire therewith in the usual manner..The main electrode is of the usual size, wherein it extends through theporcelain plug, and the lower end of the porcelainplug is tapered asshown at 19 so as to correspond with an enlarged lower portion 20 of themain electrode, which projects from the plug and below the lower edge ofthe casing 11, as shown. This enlargement produces a shoulder 21 betweenwhich and the lower end of the porcelain core or plug, an asbestosinsulating ring or gasket 22 is positioned, So as to prevent heat frombeing conducted to the core, thereby preventing heating of the latter,as well as preventing leakage when the plug is cold. The lower end ofthe main electrode 17 is enlarged as shown at 20, in order to providestrength, in 1 addition to forming a shoulder for the attachment andinterposition of the gasket or insulator, as described. Formed atthelower end of the electrode and the enlargement 20, is an invertedconical head-like portion 22, the sariie being provided withdiametrically opposite notches 23, the walls of which bevel in oppositedirections, while the opposed sides of said enlargement are beveled atright angles to the bevels of the walls of the notches 23, as shown at24, there being; a shoulder 25 formed between the enlarge- 1 nent20 andthe inverted conical enlargement 22 for a purpose to be hereinafter morefully set forth, v

Ell

Depending from the lower edge or end of the casing- 11 is a. branchelectrode 26, whichis angular and has one end portion connected to thelower edge by securing blocks 27, while the free end thereof extendsinwardly toward the enlarged head of the main electrode and is spacedtherefrom to form. the spar: gap.

It should be noted that the notched por tion is contiguous with and ofthe same size as the enlargement 20 and by providing the enlarged head22, producing. a shoulder as specified, the firing surface willheprotected from oil and like collection of foreign matter, thc'surfacesdraining by reason of the construction described.

Also owing to the fact that head of the main electrode is the notchesand beveled surfaces on its extremity no continuous surface will hepresented that would permit carbon deposits forming thereon. The mainelectrode is so arranged that one of the hcvelcd faces is disposedadjacent the ends of the branch electrode so that a perfect spark isinsured. This will present a flat surface adjacent the end of the branchelectrode so that there the enlarged provided with will he no likelihoodof the spark plug missmg while in operation. The notches serve to breakthe continuous lower edge oi the extremity, and consequently willprevent carbon deposits forming thereon to short circuit the plug. Thebeveled faces, owing to their inclination, tend to throw the explosivecharge downwardly and prevent any u-ndue backing of gases within thechamber formed between the lower end of the core and the casing, thisalso being assisted by the lower tapered formation of the plug or core,as specified. Likewise, the provision of the gasket or insulating ringsobviates the breaksulated core terminating short of ecture ing of a plugwhen the latter becomeshot, as well is cold.

From the foregoing description taken in connection with the accompanyingdrawings, it is thong it that a clear and comprehensive understanding ofthe construction,

operation, and advantages of my inventionmay be had and while I haveshown and and scope of the invention as claimed.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent, is:

A. spark plug comprising a casing, airinthe lower edge thereof, acentral electrode extending through said core and projecting from thebottom of the same below the edge of the casing, the projecting portionof said electrode being enlarged to provide a shoulder adjacent to saidcore, an insulator between said enlargement of the central electrode andthe core, said core being tapered adjacent thereto, and the lower end ofthe en larp'cnicnt of the main electrode having an inverted cone'shapcdenlargement provided with opposed beveled surfaces and a groove thereinwith opposedl" beveled notches conforming to the enlargement anddisposed at right angles to the beveled facesiirst- IHGIL tioned, and abranch electrode projecting from the lower edge of the casing to a pointadjacent the! extremity of the main electrode.

In testimony whereof, I aliixiny signa-- ture hereto.

LEE B. BENN.

as to prevent leakage when the plug

